OL2385SWUG datasheet(43/64 Pages) NXP

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NXP Semiconductors

OL2385SWUG

SIGFOX software driver

OL2385SWUG

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User guide

Rev. 2.1 — 6 April 2018

43 / 64

number and look at the SPI RX buffer values starting from the 4th byte value until the

29th. With SPI command 23 and sub command as 2, you can reset the table inside the

OL2385 to the default value of 0.

Note: NXP currently supports boards operating a TCXO only and not a standard XTAL

oscillator.

Note:

• This calibration has to be done once and done before doing the static frequency

calibration.

• This calibration is useless for RCZ3, because TCXO is used as crystal.

• This calibration makes sense for final production or certification at SIGFOX. For normal

RF evaluation, skip this and proceed to Section 7.2.2.2 "Static frequency calibration",

because temperature does not vary that much in normal test environment.

7.2.2.2 Static frequency calibration

The next command for any device is Static frequency calibration. This command also

needs to be done only once after flashing new firmware on the OL2385. The Static

frequency calibration command is optional. If you choose to skip this command, some

TX and RX scenarios might not work. The crystal used on the boards has, sometimes,

an initial offset. Therefore, the actual frequencies from the board differ slightly from the

commanded frequency. For example, if a command to start an unmodulated continuous

wave at 868.13 MHz is given, on a spectrum analyzer the peak of the spectrum is not

exactly at 868.13 MHz. It is at an offset as shown in Figure 31. This offset is variable

for different crystals, but on a single board it is relatively fixed and is needed to be

compensated. This compensation is not required for an RCZ3 device, because it uses a

TCXO.

Note: NXP currently only supports boards operating a TCXO and not a standard XTAL

oscillator.

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